G20 subnational legislatures
Lucic (2026) 
Harvard data Repository

For any question, contact lucic.nicolas@gmail.com

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Why the G20 countries ?

We selected the G20 countries for the purposes of this data repository. They combine different political systems, regimes, polity types and democratic/autocratic typologies. They also combine countries with different political and cultural traditions, languages and religions. They include numerous middle income and developping countries such as Brazil, Russia, China, India, Indonesia, Argentina, South Africa, Mexico and Turkey and represent more than half the world's population, GDP, foreign trade and GHG emissions. 
Some of them are federal and other are unitary states, which means that subnational legislatures have very different responsibilities from one country to the other, and represent a form of legislative (federal), quasi-legislative (regional) or mixed administrative-legislative bodies. 

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Framework

Our framework for data collection was always consistent and stayed the same for every single country. We first checked if there were central /statistical elections commissions or reports that would compile all subnational legislature data, regarding, for example, number of seats, political parties, majorities and so on. If these were unavailable, I then checked for the individual subnational legislature websites as they usually compile present and past members and define the number of seats. Though, there is a weakness in this logic : usually, these websites only present currently sitting members, and not empty ones (for various reasons such as death, resignations, political shuffling, ...)  thus potentially undercounting the real total number of seats available in these legislatures. Indeed, there was a necessity for double checking which I did through media articles, other official reports and official law (when available). For ease of access, I checked whether there were centrally located informations. For instance, Wikipedia has articles for the subnational legislatures of some countries (Argentina, Brazil, Canada, Germany, Mexico, Russia, ...). I included it as sources when Wikipedia reported data was consistent with all data reported by other sources. 

All sources for individual legislature size can be found in a separate file : READ_ME_Sources_lucic_G20_subnational_legislatures.

Note that due to translation difficulties, it was sometimes complicated to determine who was officially in or out these subnational legislatures. For example in Turkey, it was hard to understand whether the heads of legislatures should be counted in. Ultimately, I decided to count them in across the board. 

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How to actually use these datasets ?

Each dataset has been divided on a per country basis with a dedicated Excel file. Within each dataset, one might find one to three sheets, depending on whether the areas of interest, for instance only the metropolitan subnational units or include small and overseas territories not considered as part of the mainland country. All individual country datasets are titled with the "country name" and "subnational legislatures 2025". 

Each sheet for each dataset follows the same structure. There are seven columns from left to right. 
The lefthand most column has names of subnational units. 
The second column lists the number of seats in the subnational lower house. 
The third column lists the number of seats in the subnational upper house. 
The fourth column lists the total number of seats in the subnational lower + upper house. 
The fifth column lists the population taken from the latest national census (taken from 2020 to 2025). If not available, we use latest estimated population data available, calculated by the national statistical office of the country. Note that population includes foreigners that cannot vote, which is relevant for countries like Saudi Arabia. 
The sixth column indicates population per subnational seat. To obtain the individual numbers, I divide the fifth column value by the fourth column value. The seventh and final column is the area per km². It includes land and water areas. These data are publicly available and easy to find, for example, Wikipedia usually lists it for all countries and is consistent with reported data. 

Note that if the subnational unit is unicameral, as most in this sample are, the seats have been attributed to the second column listing all lower house seats per subnational unit. 

You will also find a ready-for-analysis file regrouping all data named "G20 subnational legislatures all data formalized 2025". 
There are two sheets in this excel file, the first presents all subnational legislatures sorted by population size, from lowest to highest, with small and overseas territories; the second sheet presents all subnational legislatures sorted by population size, from lowest to highest, with mainland territories only. They have the exact same construction and framework as the previous description, with one difference : there are now eight columns, with the lefthand-most column being the country name. The second column in this dataset is the first column from individual country datasets, and so on. 

Every country file usually has one or two sheets (Australia, P.R. China, United States of America) per file. 

France has three sheets as there are three types of samples one might want to study : only metropolitan France, metropolitan France + overseas regions (that are administratively exactly on par with metropolitan France) and all French territories, including all French regions (mainland + overseas regions) and overseas French collectivities (special status territories, such as French Polynesia or New Caledonia/Kanaky, among others).

Depending upon one's point of view, the United Kingdom should have two (U.K. mainland and U.K. mainland + overseas territories) or six (two previous + each nation's legislatures) sheets. For ease of access, understanding and information dissemination, I presented all six possible presentation variations for the United Kingdom's subnational legislatures. 

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Remarks and comments

One must note that gathering data for Chinese subnational legislatures was particularly complicated and not very transparent as it changes in a dynamic manner during the 5-year mandates. Also, as there does not seem to be a centrally located file or dataset gathering the subnational legislature changes, one must expect small changes (usually in the +/- 10 range, usually less than 2%) between the time of writing and publication. 

Moreover, the United Kingdom (GBR) seems to have chosen a higher level of devolution than other countries since subnational units are much more numerous and less populous comparatively with every other country in the G20 sample. For the sake of clarity, I considered all English County councils (21), all metropolitan Boroughs (36), all unitary authorities (62) and London Councils (32) with the City of London council excluded (it is an archaic council that represents both people and businesses ; mostly it represents thousands of businesses and only 8000 people) for a total of 151. Scotland has 32, Wales has 22 and Northern Ireland 11. The grand total for the United Kingdom is thus 216. Overseas territories (Jersey and Guernsey included) can be included for 12 added legislatures, with a total of 228 U.K. + Overseas territories of the UK subnational legislatures. 

There is separation between lower and higher chambers, although these are irrelevant in the case of unitary territories as it is rather a practice of federal countries. No federal countries in our sample have bicameral legislatures for every single existing subnational legislature (even the U.S. has 49/50 states have bicameral). Some federal countries have unicameral only (Canada, Germany and Mexico) subnational legislatures and partial bicameral legislatures [(Argentina (8/24) ; Australia (5/8) ; India (5/32)].

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Licences : CC BY-NC-SA 

For any questions or for potential commercial use (which I will most likely allow), contact me : lucic.nicolas@gmail.com

